chromium/chrome/test/data/extensions/bad_underscore/manifest.json

{
  "name": "foo",
  "version": "1",
  "manifest_version": 3,
  "description": "Test that an extension with a directory with a trailing underscore is still allowed to load (it's a warning, not an error). Note the directory here is incorrectly named `_locale` instead of `_locales`."
}